Comparison between STIR and T2-weighted SPAIR sequences in the evaluation of inflammatory sacroiliitis: diagnostic performance and signal-to-noise ratio

Abstract Objective: To compare two different fat-saturated magnetic resonance imaging (MRI) techniques-STIR and T2 SPAIR-in terms of image quality, as well as in terms of their diagnostic performance in detecting sacroiliac joints (SIJ) active inflammation. Materials and Methods: We included 69 consecutive patients with suspected spondyloarthritis undergoing MRI between 2012 and 2014. The signal-to-noise ratio (SNR) was calculated with the method recommended by the American College of Radiology. Two readers evaluated SIJ MRI following ASAS criteria to assess diagnostic performance regarding the detection of active SIJ inflammation. T1 SPIR Gd+ sequence was used as the reference standard. Results: The mean SNR was 72.8 for the T1 SPIR Gd+ sequence, compared with 14.1 and 37.6 for the STIR and T2 SPAIR sequences, respectively. The sensitivity and specificity of STIR and SPAIR T2 sequences did not show any statistically significant differences, for the diagnosis of sacroiliitis with active inflammation. Conclusion: Our results corroborate those in the recent literature suggesting that STIR sequences are not superior to T2 SPAIR sequences for SIJ evaluation in patients with suspected spondyloarthritis. On 1.5-T MRI, T2-weighted SPAIR sequences provide better SNRs than do STIR sequences, which reinforces that T2 SPAIR sequences may be an advantageous option for the evaluation of sacroiliitis.研究目的：对比两种脂肪饱和磁共振成像（fat-saturated Magnetic Resonance Imaging, MRI）技术——短时反转恢复序列（STIR）与T2 SPAIR序列的图像质量，以及二者在检测骶髂关节（Sacroiliac Joints, SIJ）活动性炎症中的诊断性能。 材料与方法：纳入2012至2014年间收治的69例疑似脊柱关节病并行MRI检查的连续性患者。采用美国放射学院推荐的方法计算信噪比（Signal-to-Noise Ratio, SNR）。由两名阅片者依据国际脊柱关节炎评估协会（Assessment of SpondyloArthritis international Society, ASAS）标准对骶髂关节MRI图像进行评估，以分析二者检测活动性SIJ炎症的诊断性能。以T1 SPIR钆增强序列作为参照标准。 结果：T1 SPIR钆增强序列的平均信噪比为72.8，STIR序列与T2 SPAIR序列的平均信噪比分别为14.1与37.6。STIR序列与T2 SPAIR序列在诊断伴活动性炎症的骶髂关节炎时，其灵敏度与特异度均无统计学显著差异。 结论：本研究结果与近期文献结论相符，即在疑似脊柱关节病患者的骶髂关节评估中，STIR序列并不优于T2 SPAIR序列。在1.5T MRI检查中，T2加权SPAIR序列的信噪比优于STIR序列，进一步证实T2 SPAIR序列可作为骶髂关节炎评估的优选方案。